Evaluating suspected CHF in dogs and cats: Why the full clinical picture matters

When evaluating dogs and cats with suspected congestive heart failure (CHF), veterinarians should consider the patient's complete clinical picture rather than rely on individual signs or test results, according to a session at the 2026 New York Vet Show.

During a talk held at the Jacob K. Javits Convention Center in New York City, Sergio Serrano, LV, DVM, DACVECC, co-director of the Emergency and Critical Care Department at Guardian Veterinary Specialists, discussed the initial emergency evaluation of patients with suspected heart disease, emphasizing patient history, physical examination, and diagnostic imaging.

Avoid tunnel vision during the initial evaluation

Serrano cautioned clinicians against assuming that every clinical sign in a patient with a heart murmur or known cardiac disease is necessarily related to the heart.

“The first thing to do when we're facing a patient that might or might not have heart disease or congestive heart failure is avoid the tunnel vision,” he said.

For example, some small-breed dogs may have heart murmurs for years before developing clinical signs of CHF. Similarly, pulse deficits in older, large-breed dogs do not automatically indicate clinically significant disease. Serrano encouraged clinicians to consider whether the patient's respiratory signs are consistent with cardiac disease and investigate other potential explanations.

He also cautioned against relying on historical diagnoses without supporting diagnostic information. He described patients with longstanding respiratory complaints who had received repeated courses of medication for presumed bronchitis without a thorough diagnostic workup, including radiographs or bloodwork.

Serrano also highlighted clinical findings that may help clinicians distinguish CHF from other causes of respiratory distress.

“A patient with pulmonary edema does not make noises,” he said, explaining that loud respiratory sounds should prompt clinicians to consider other causes of respiratory distress rather than assume the patient has pulmonary edema. He also noted that patients with CHF typically do not exhibit fever, unless when caused by endocarditis or myocarditis.

Cats with heart disease, Serrano added, do not cough.

Using POCUS to assess cardiopulmonary findings

Point-of-care ultrasound (POCUS) can help clinicians rapidly evaluate patients with suspected cardiopulmonary disease. Serrano reviewed several findings to assess during the examination, including cardiac enlargement, pulmonary fluid, and pleural or pericardial effusion.

He discussed the left atrium-to-aorta (LA) ratio as an indicator of cardiac congestion, identifying ratios greater than 1.8 in cats and 1.5 in dogs as suggestive of enlargement and congestion.

However, he emphasized that cardiac congestion and pulmonary edema are not interchangeable findings. Although cardiogenic pulmonary edema does not occur without cardiac congestion, patients can have congestion without pulmonary edema, including animals already receiving cardiac medications.

A normal LA ratio can help rule out pulmonary edema, according to Serrano, while an elevated ratio should be interpreted alongside other clinical and diagnostic findings.

He also reviewed B-lines, ultrasound artifacts associated with fluid in the lungs. Their presence can support the identification of an interstitial lung pattern, but clinicians must consider other potential causes rather than automatically attributing the finding to CHF. For example, localized B-lines may occur with pneumonia.

Additional POCUS applications discussed included identifying pleural effusion, distinguishing pleural from pericardial effusion, assessing for pneumothorax, and evaluating ventricular size. A markedly collapsed left ventricle can indicate severe hypovolemia, Serrano explained.

Considering the patient's condition during imaging

Thoracic radiographs provide additional information when evaluating suspected cardiac disease. Serrano discussed assessing cardiac size, the pulmonary vessels, and evidence of pulmonary edema. He also cautioned against placing unstable respiratory patients in positions that could compromise ventilation simply to obtain diagnostic images.

Together, patient history, physical examination, POCUS, and radiographs can help clinicians evaluate suspected CHF and distinguish cardiac disease from other causes of respiratory distress. Throughout his presentation, Serrano returned to the importance of interpreting findings in context rather than allowing an individual clinical sign or imaging result to determine the diagnosis.

Reference

Serrano S. The broken heart. How to fix it when Tinder won't (managing heart failure in the ER). Presented at: NY Vet Show; October 29, 2026; New York, NY.